With such airbag modules, considerable difficulties are regularly encountered when it comes to maintaining specified separating distances which must be overcome in order to activate the horn, because this involves a plurality of components made of a variety of materials, and because tolerances with respect to the specified real production dimensions, which may be acceptable in each individual case, may add up one to another.
If the separating distances within the actuating area of the cover cap are too large in a single place only, the horn cannot be activated by the-application of the usual pressure, so that the driver must make a second attempt whilst using a greater application pressure. This leads to the horn signal being delayed, thereby causing or increasing the danger to the traffic.
If the separating distances are too small, the horn signal may be activated unintentionally or by the vibrations of the vehicle, causing irritation to the driver and to other road users.
Although a plurality of measures have already been proposed to set a specified actuation stroke for the activation of the horn signal with only small tolerances to the nominal value, these are in most cases too cost-intensive, and not sufficiently reliable in operation when taking into account influences of temperature and material fatigue over the normal lifetime of a vehicle.
An object of the invention is, therefore, to ensure that for an airbag module of the previously mentioned type tightly tolerated separating distances for the activation of the horn can be achieved without encountering the previously mentioned disadvantages. In particular it must be guaranteed that, taking into consideration the required elastic resetting forces for the actuation device, a habitual and accustomed activating range can be maintained under all possible external conditions, so that no additional danger to the traffic is created by deviations from these values.
This object is met, according to the invention, in that a flat actuating element is provided between the horn foil and the cover cap, which has a consistently defined spacing from the horn foil, which essentially extends in a plane, and in that range spacers in the form of pins, webs or similar are provided between the actuating element and the cover cap, to provide an approximately constant separation distance between the actuating element and the cover cap, at least across the entire actuating area.
The interposed flat actuating element provides the advantage that the horn foil, as recommended, can be arranged in a plane and that the internal shape of the cover cap need not be taken into consideration. On the other hand, the cover cap may be given the shape that best meets its general requirements without having to adapt it to the arrangement of the horn foil. In other words, the requirements concerning the arrangement and the shaping of both the horn foil and the cover cap can be made independent from each other by means of the interposed actuating element according to the invention. Furthermore, in the design of the actuating element there is no restriction as to the choice of the type of material, and equal separating distances can be achieved by simple means over the entire actuating area.